Scurvy

Deficiency disease resulting from the lack of vitamin C.

This might seem a strange subject to cover here, but the ailment is so connected to food and diet it cannot be ignored.

It has been said that the struggle to rid ships of this nutritional deficiency disease proved as effective a barrier to sea exploration as gravity was to space equivalent. On Vasco da Gama"s first voyage to India in 1498 more than half his crew died of it.

Even in the 17th century, the trip to India would claim at least one out of five men. Part of the trouble being that lack of fruit and vegetables (particularly during the winter months) meant crews suffered from "winter rash" - a pre-scurvy symptom - even before they left shore.

It should also be remembered that the importance (or indeed the source) of vitamin C was not understood at the time, for although the Chinese grew ginger on their ships as early as the 5th century to prevent scurvy, they had no idea why the consumption of it helped.

Even in the early 17th century, many "experts" believed that scurvy wasn"t caused by too little fresh food, but too much salt food - for which (apart from carrying live animals for slaughter) nothing could be done. Malt, cider, pickles and sauerkraut all seemed to work but no one knew why!

Finally, at the end of the 18th century it was accepted, by the British navy at least, that the juice of citrus fruits was the only medicine that could conquer a disease that was killing more seamen than enemy action.

Even then they made the mistake of preferring limes - which were more accessible in the West Indies, to harder to get Mediterranean lemons - limes containing much less vitamin C. See 'Exploration at Sea, Diet'